CVE-2020-1210
📋 TL;DR
This is a critical remote code execution vulnerability in Microsoft SharePoint that allows attackers to run arbitrary code by uploading a specially crafted application package. Exploitation requires user interaction to upload the malicious package, affecting SharePoint servers running vulnerable versions. Successful exploitation grants the attacker privileges equivalent to the SharePoint application pool and farm account.
💻 Affected Systems
- Microsoft SharePoint Server
- Microsoft SharePoint Foundation
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the SharePoint server farm, allowing attackers to execute arbitrary code with SharePoint farm account privileges, potentially leading to data theft, lateral movement, and full control of the SharePoint environment.
Likely Case
Attackers upload malicious SharePoint packages through social engineering or compromised accounts, gaining code execution on SharePoint servers to steal sensitive data or deploy additional malware.
If Mitigated
With proper access controls and monitoring, exploitation attempts are detected and blocked before successful compromise, limiting impact to isolated incidents.
🎯 Exploit Status
Exploitation requires user interaction to upload malicious package. No public exploit code was available at time of advisory publication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Security updates released in May 2020 (specific KB numbers in Microsoft advisory)
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1210
Restart Required: Yes
Instructions:
1. Download appropriate security update from Microsoft Update Catalog. 2. Apply update to all SharePoint servers in farm. 3. Restart SharePoint services. 4. Test functionality.
🔧 Temporary Workarounds
Restrict SharePoint Package Uploads
windowsTemporarily disable or restrict upload of SharePoint application packages (.app files) until patching can be completed.
Configure SharePoint Central Administration to restrict package upload permissions
🧯 If You Can't Patch
- Implement strict access controls on SharePoint package upload functionality
- Monitor for suspicious package uploads and implement application whitelisting
🔍 How to Verify
Check if Vulnerable:
Check SharePoint version against affected versions listed in Microsoft advisory. Review if security update KB numbers are installed.Check Version:
Get-SPFarm | Select BuildVersionVerify Fix Applied:
Verify security update KB numbers are installed via Windows Update history or PowerShell: Get-HotFix -Id KB4552041 (example KB)📡 Detection & Monitoring
Log Indicators:
- Unusual SharePoint package uploads
- Failed package validation events
- Suspicious activity in SharePoint ULS logs
Network Indicators:
- Unusual outbound connections from SharePoint servers
- Suspicious file transfers to SharePoint
SIEM Query:
source="SharePoint" AND (event_id=6398 OR event_id=6399) AND package_upload="*"